And if you’re going to have the world’s dominant mobile platform, then you ought to be the one selling music subscriptions that work on it, because that could help your customers stick to that platform. No sense in handing that feature over to Spotify, which works fine on iPhones and Kindles, too.

And something that knitted Android and YouTube together — combining a mix of free, paid, mobile, audio and video — could be great.

But that’s not what we’re going to see this week.

Music folks I talked to today expect the Google Play version to be paid-only — no free teaser tier, like Spotify has — and without any features that will set it apart from rivals.

And when YouTube launches its service — as best as I can tell, talks with the Big Three labels are all but completed — that service will likely run parallel to, but not connected with, the Play version. Which means none of the free music that people can get on YouTube will help sell Play subscriptions.

But music subscriptions are an old idea that still really haven’t caught on in a big way. Spotify has six million paying customers worldwide, but its backers concede that it’s still a long way from mainstream. And none of its competitors are even close to those numbers.

If Google really wanted to make subscriptions work, instead of simply offering them as a feature most people won’t use — like the music store it opened up in 2011 — it ought to take the time to get this one right the first time.

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